HardwareEver wanted to rip open an NFC travel card to see how it all works? One engineer has done just that and it’s way cooler than you’d thinkWhen you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.
HardwareEver wanted to rip open an NFC travel card to see how it all works? One engineer has done just that and it’s way cooler than you’d thinkWhen you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.
When you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.
(Image credit: Dowell via Getty Images)
To use the Montreal subway, you tap a paper ticket against the turnstile and it opens. But how does it work? And how can the ticket be so cheap that it’s disposable? I opened up the tiny NFC chip inside to find out more… 1/15 pic.twitter.com/OlQkkikp0mJune 23, 2024
To use the Montreal subway, you tap a paper ticket against the turnstile and it opens. But how does it work? And how can the ticket be so cheap that it’s disposable? I opened up the tiny NFC chip inside to find out more… 1/15 pic.twitter.com/OlQkkikp0mJune 23, 2024
The largest part of the whole setup is the antenna—it picks up the 13.56 MHz radio wave signal from the sensor’s transmitter and it also provides the means to power the chip. The wave’s tiny amount of energy is all that’s required. But given that the processor (or rather, the digital controller) is smaller than a grain of salt, it’s not surprising that so little power is required.
It’s so small that Shirriff ran into all kinds of problems trying to remove it from the card and etch down its layers, to see the logic circuits inside. In his own words, just “bumping the chip or even breathing on it can send the chip flying perhaps never to be seen again.”
Processor die images are things of wonder and we’ve all gazed and wondered at the work of the likes ofFritchen Fritz. This thing is on another level altogether, though. Not because it comprises billions of transistors (it doesn’t) or because it’s made on a cutting-edge process node (it very much isn’t)—it’s the fact that you can see the individual transistors making up the logic gates that process the data.
Shirriff estimates that the chip is made on a 180nm process node, as the transistor’s layers are a little outside the limits of his optical microscope. And speaking of microscopic, the chip’s dimensions are absurdly small: 570 x 485 microns (millionths of a metre), and between 70 and 120 microns thick. To give this some kind of context, albeit a rather silly one, you could fit more than 2,200 of them inside the AD102 GPU used in an NvidiaGeForce RTX 4090.
You might think it’s somewhat ridiculous that these chips are manufactured to be disposable. After all, once the card wears out or is no longer accepted, they’re not recycled in any way. But as Shirriff points out, NFC chip manufacturers, such asNXP Semiconductors, don’t sell them individually—you buy the entire silicon wafer that they’re made on for a cost of up to $12,000 depending on the size.
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Image1of3(Image credit: Ken Shirriff)The controller chip is the tiny black dot in the bottom right-hand corner.(Image credit: Ken Shirriff)The NFC card’s controller next to a grain of salt.(Image credit: Ken Shirriff)Most of the chip is logic for processing instructions.
Image1of3(Image credit: Ken Shirriff)The controller chip is the tiny black dot in the bottom right-hand corner.(Image credit: Ken Shirriff)The NFC card’s controller next to a grain of salt.(Image credit: Ken Shirriff)Most of the chip is logic for processing instructions.
Image1of3
(Image credit: Ken Shirriff)The controller chip is the tiny black dot in the bottom right-hand corner.(Image credit: Ken Shirriff)The NFC card’s controller next to a grain of salt.(Image credit: Ken Shirriff)Most of the chip is logic for processing instructions.
(Image credit: Ken Shirriff)The controller chip is the tiny black dot in the bottom right-hand corner.(Image credit: Ken Shirriff)The NFC card’s controller next to a grain of salt.(Image credit: Ken Shirriff)Most of the chip is logic for processing instructions.
(Image credit: Ken Shirriff)The controller chip is the tiny black dot in the bottom right-hand corner.
(Image credit: Ken Shirriff)The controller chip is the tiny black dot in the bottom right-hand corner.
(Image credit: Ken Shirriff)
(Image credit: Ken Shirriff)
(Image credit: Ken Shirriff)
The controller chip is the tiny black dot in the bottom right-hand corner.
The controller chip is the tiny black dot in the bottom right-hand corner.
(Image credit: Ken Shirriff)The NFC card’s controller next to a grain of salt.
(Image credit: Ken Shirriff)The NFC card’s controller next to a grain of salt.
(Image credit: Ken Shirriff)
(Image credit: Ken Shirriff)
(Image credit: Ken Shirriff)
The NFC card’s controller next to a grain of salt.
The NFC card’s controller next to a grain of salt.
(Image credit: Ken Shirriff)Most of the chip is logic for processing instructions.
(Image credit: Ken Shirriff)Most of the chip is logic for processing instructions.
(Image credit: Ken Shirriff)
(Image credit: Ken Shirriff)
(Image credit: Ken Shirriff)
Most of the chip is logic for processing instructions.
Most of the chip is logic for processing instructions.
That single wafer will give you over 200,000 usable dies, so NFC card makers are only looking at six cents per die, which will only be a tiny fraction of the manufacturing cost of the entire card. Similar chips, ones with more security features, are used in contactless bank cards, hotel room ‘keys’, and smartphones of course.
Your next upgrade(Image credit: Future)Best CPU for gaming: The top chips from Intel and AMD.Best gaming motherboard: The right boards.Best graphics card: Your perfect pixel-pusher awaits.Best SSD for gaming: Get into the game ahead of the rest.
Your next upgrade
(Image credit: Future)Best CPU for gaming: The top chips from Intel and AMD.Best gaming motherboard: The right boards.Best graphics card: Your perfect pixel-pusher awaits.Best SSD for gaming: Get into the game ahead of the rest.
(Image credit: Future)
Best CPU for gaming: The top chips from Intel and AMD.Best gaming motherboard: The right boards.Best graphics card: Your perfect pixel-pusher awaits.Best SSD for gaming: Get into the game ahead of the rest.
Shirriff breaks down what each part in the chip does and it’s well worth your time reading through the whole blog post.
In the space of a few decades, we’ve gone from using PINs with magnetic strips, and then so-called smart chips, to microscopic, disposable silicon to pay for goods and travel on public systems. It’s a tribute to the skills of engineers and scientists that we take such things for granted.
I kind of miss my high school days of messing about with 741 op-amps to make lights go all flashy-flashy in the electronics lab—I really should have stuck at it!
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Epic CEO Tim Sweeney says tech leaders are ‘pretending to be Republicans’ to gain favor with Trump, skirt antitrust laws, and ultimately ‘rip off consumers and crush competitors’
If you’re trying to convince me your ‘companionship’ robot is ‘lifelike’, maybe don’t rip her face off in the demo video
Square Enix launches new anti-harassment policy to protect its employees and partners from abusive fans
The Sims begins its 25th anniversary celebration next week with a Behind The Sims episode of news and announcements
Path of Exile 2 numberlord spends 16 straight days killing rare monsters to prove that a stat that makes loot better makes better loot
Palestinian developer raises more than $200,000 to make Dreams on a Pillow, a game about the horrors of the 1948 Nakba
Piranha Games will lay off employees after Mechwarrior 5: Clans ‘performed below projections’
Marvel Rivals’ latest update quietly killed the game’s burgeoning mod scene
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